Anyone know the part # and/or where I can buy a replacement blower motor for an Armstrong Ultra SX 90 gas furnace? Model # of furnace is GUK075 D10

Most service people just remover the motor and replace it with a universal truck stock motor of the same horse power. Usually the rotation can be changed by wire selection and they also replace the motor run capacitor. NO matter which type of motor you get make sure to get a brand new capacitor to match it.

Graingers,HVAC supply houses and some Home Depot/Lowes have a motor that will fit your unit.

One other item. I cannot find your model number listed so it is possible you have a variable speed unit. If that is the case I suggest you contact a local HVAC company to do the repairs.

Thanks for the quick reply. I will check Home Depot for the motor and the motor capacitor.

A description of the furnace is here:

Design Temp Inc. Residential Heating Armstrong SX90 (http://www.designtemp.com/dt_ProductsResArmGFSX90.html)

8. Continuous low-speed fan capability - so I'm assuming it's a fixed speed and not a variable speed unit?